Electromagnetic pulsing device



May 24, 1966 v. D. ROOSA 3,253,101

ELECTROMAGNETIC PULSING DEVICE Filed Feb. 4, 1964 2 Sheets-Sheet 1 f 32 as FIG! INVENTOR. VERNON D. ROOSA army, MMMW ATTORNEYS May 24, 1966 v. D. ROOSA ELECTROMAGNETIC PULSING DEVICE 2 Sheets-Sheet 2 Filed Feb. 4, 1964 FIG. 6

INVENTOR VERNON D. ROOSA BY ATTORNEYS United States Patent 3,253,101 ELECTROMAGNETIC PULSING DEVICE Vernon D. Roosa, West Hartford, Conn. Hartford Machine Screw Co., Box 1440, Hartford, Conn.) Filed Feb. 4, 1964, Ser. No. 343,190 7 Claims. (Cl. 200-87) This application is a continuation-in-part of application Serial No. 198,665, filed May 29, 1962, now abandoned.

This invention generally relates to switching devices of the electromagnetically opera-ted type and is more specifically concerned with an improved switching device of the type generally referred to as a pulser or vibrator.

It is a primary object of this invention to provide an improved pulser that utilizes relatively few component parts to provide an extremely low cost lightweight device having unusually high reliability and long life.

It is a further object of this invention to provide an improved pulser that provides low cost yet effective contact arc suppression so as to permit use in application where electrical noise and long life requirements have heretofore required relatively complex and expensive devices.

' Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a perspective view, partially in cross section, illustrating one embodiment of my improved switching device;

FIG. 2 is an elevational view of the device of FIG. 1;

FIG. 3 is an exploded view of the armature assembly of the device of FIGS. 1 and 2;

FIG. 4 is a schematic circuit diagram of an embodiment of my invention shown connected to a load device;

FIG. 5 is a perspective view showing an improved mounting arrangement for the switching device of FIGS. 1 and 2;

FIG. 6 is an elevational view partly broken away of I another embodiment of my improved switching device;

FIG. 7 is a cross-sectional view taken along lines 77 of FIG. 6; and

FIG. 8 is a fragmentary view taken along the lines 88 of FIG. 6.

Referring now to the drawings and particularly to FIGS. 1 and 2, it is seen that my improved switching device generally comprises a base 10 on which is supported an electromagnet generally designated 12 which cooperates with an armature assembly generally designated 13 whose movement controls a pair of contacts 14 and 15, the entire assembly being enclosed within a suitable housing 17 secured to the base.

The base 10 is preferably formed from a suitable insulating material and is provided with a recess 20 in which is received the magnet assembly 12. This magnet assembly comprises a generally cylindrical core 21 on which is wrapped the desired number of turns of insulated wire to form the solenoid or coil 22 which is positioned between a pair of fiber washers 23. In the illustrated embodiment one end of coil 22 is electrically connected to core 21 .and the lower end of the core extends through base 10 to a terminal 25 for connection to a suitable power source. The fiber washers and coil are securely positioned on the core which is in turn positioned on the base by a pair of spring washers 27.

The armature assembly 13 is supported for cooperation with electromagnet 12 by a generally U-shaped yoke 28 whose ends 29 are embedded in and supported by the ice insulating base 10 and is supported for movement relative to core 21 and yoke 28 by a coil or spiral spring 32 whose ends and 3-1 engage suitable notches 33 and 34 provided in the arms of the yoke 28. Preferably, armature 13 is fabricated from two identically shaped stamped steel members 36 and 37 which are provided with generally semi-circular, centrally located ribs 38 and 39, each of which has a grooved projection 40 formed thereon. When the members 36 and 37 are fastened together as shown in the drawings (such as by welding) with the coil spring disposed in the generally circular passageway formed by ribs 38 and 39, one or more turns of the coil spring 3 2 are tightly clamped between the grooved portions 40 so as to produce torsional stressing of the coil spring 32 upon rotational movement of the armature. Such a spring mounting not only provides a durable and fatigue resistant torsion spring mounting for the armature but also helps to isolate the armature from extraneous vibrations and to damp any unwanted movement of the armature. It is also to be noted that armature members 36 and 37 are provided with notched ends 35 which are contoured in mating relationship to the profile of the core 21 thereby to minimize the physical displacement necessary between the armature and the core to provide a given armature travel and at the same time reduce the power requirements of the electromagnet assembly by minimizing the air gap.

In accordance with a preferred feature of this invention, the yoke 28 as well as the armature 13 and spring 32 are formed from suitable electrically conductive materials so as to act as current carrying members in the internal electrical circuit of this pulser. Accordingly, the contact 14 is secured directly to the armature and the contact 15 is positioned for engagement therewith by its mounting on conductive spring 42 which in turn is suitably afiixed to terminal member 43 imbedded in base 10. As most clearly seen in FIG. 1, one end of coil 22 is secured by welding or brazing to yoke 28 thereby to establish circuit continuity from terminal 25 (the core of the electromagnet) through coil 22, yoke 28, spring 32,

' armature 13, contacts 14 andlS, and spring support 42 to 1 and 43 to a suitable source of electrical energy, for example, a DC. voltage source, the coil will be energized through the aforedescribed circuit so as to produce a magnetic field which attracts the armature to the core thereby separating contacts 14 and 15 to de-energize the electromagnet. Upon de-energization of the coil, the spring returns the armature to its rest position wherein contacts 14 and 15 engage thereby providing oscillatory armature action. The period of oscillation of armature 13 is, of course, determined by such characteristics as the mass of the armature, the stilfness of the spring, etc.

It is to be understood that the necessary circuit connections which have been described as including the various structural members of the improved pulser can, of course, be provided by conventional conductors suitably aflixed between appropriate connection points. It has been found, however, that many low-power applications can etficiently and economically utilize the illustrated arrangement.

The pulser just described is suitable for use in many applications which require a pulsating power particularly from a direct current source and a typical application is illustrated in my copending application Serial No. 297,172, entitled Electric Pump, filed July 16, 1963, now US. Patent No. 3,174,433. Such a pump requires a pulsating DC. power source having accurately determined pulse lengths to permit accurate pumping action while at the same time requiring that the pulse length be variable to 3 achieve different pump rates. Such variations can, of course, be achieved by the described pulsing device through appropriate variation of the characteristics of the DC. power supplied to the terminals of the pulser.

In order to provide a relatively dust-free atmosphere forbperation of this pulser while at the same time providing mechanical protection for the described assembly, there is provided a housing or enclosure can 17 which is secured to a rim 46 on the base 10. Can 17 is dimensioned toengage and compress a spring washer 48 which is secured by rivet 49 to the upper end of the yoke thereby to stabilize the yoke and armature assembly against shock and vibration.

In the illustrated embodiment there is provided novel structure for contact are suppression, which structure includes an inexpensive unidirectional conducting device such 'as a disc-shaped selenium cell 51 which is positioned between two conducting washers 53, the washers and cell being secured to yoke 28 by a rivet 49 formed of nylon or other suitable insulating material, the washers serving to electrically connect the cell to the yoke and the enclosure or can 17. By forming the enclosure from conductive material such as aluminum, connection of the enclosure to the circuit ground as shown in FIG. 4 will provide contact are suppression that is desirable whenever the contacts 14 and 15 must separate a load including an inductive device such as the coil 22, it being understood that cell 51 is poled to conduct the inductive surge around the contacts.

As best seen in FIG. 5, the connection of metallic can 17 to ground is easily and economically achieved by the pulser mounting arrangement wherein a metallic clip 55 is secured to a mounting surface and engages the can 17 so as to support the entire pulser assembly while at the same time providing the desired ground connection. As best seen in FIG. 4, such an arrangement is schematically illustrated with a circuit including a suitable grounded DC. power source 57 having its positive terminal connected to terminal 43 of the pulser. Through the previously described internal connections, contacts 14 and 15 establish connection to coil 22 whose core acts as terminal 25 which is connected to a suitable load device such as the inductive load of the pump disclosed in my aforementioned copending application. The unidirectional device 51 is connected to ground through engagement of the can 17 with a mounting clip 55 which is in turn secured to a suitable ground location as, for example, the frame of an automobile.

Referring now particularly to FIGS. 6, 7 and 8, there is shown another embodiment of the invention in which like numerals refer to like parts described in the embodiments of FIGS. 1-3. In this second embodiment, one end of the electromagnet 12 is electrically connected to the core 21 as at a. The other end of the electromagnet 12 is electrically connected to the U-shaped electrically conductive yoke 28 in any suitable manner as by being welded to an arm thereof as shown at 2%. The arms of the yoke 28 are deformed as best shown in FIGS. 7 and 8, so as to provide peripheral recesses 28a having a pair of shoulders 28c. The peripheral recesses 28a are curved so as to conform to the curvature of the ends 30, 31 of the spiral spring 32. A bridging member 24, formed of electrically conductive material, is mounted with its ends positioned in the recesses 28a with the shoulders 28c serving as abutments to positively fix the position of the bridging member 24 relative to the yoke. The ends of the bridging member 24 are bifurcated to provide a gap for receiving the ends 30, 31 of the spiral spring 32 and to support the same against rotation relative to the yoke. The bifurcated ends engage the arms of the yoke to provide a good electrical connection therebetween.

Mounted on the bridging member 24 is a fixed contact 14a which is positioned to engage a movable contact 15 mounted on resilient spring arm 42a.

As best shown in FIG. 6, conductive spring arm 42a is provided with an end 42b which is laterally bent toward the armature 13 and terminates in a curved end portion for engaging an insulating button 26 mounted on the armature 13. Preferably, the curved end projection 42b is slightly spaced from the armature 13 when the electromagnet 12 is not energized so as to assure engagement between contacts 14a and 15.

In the embodiment of the invention illustrated in FIGS. 68, it is apparent that the electromagnet 12 is connected in series with one of the arms of the yoke 28, the bridging member 24, contacts 14a, 15 and resilient spring arm 42a. Thus, in this embodiment of the invention, the spiral spring 32 and the armature 13 are not connected in series with the electromagnet. The electrical circuit for the disc-shaped selenium cell 51 remains the same as shown in FIG. 4 with the three legs of the spring washer 48 engaging the can 17 which is grounded as hereinbefore described.

As best shown in FIG. 7, one or more of the centrally disposed turns of spring 32 are tightly clamped between the grooved portions 40 formed by the curved ribs 38 and 39 to produce torsional stressing of the spring 32 upon rotational stressing of the remaining turns of the spring when the armature is rotated. As with the embodiments of FIGS. 1-3, the turns of spring 32 on at least one side of the grooved portions 40 have a slight annular clearance with the curved ribs 38 and 39 to permit the unrestrained enlargement of these turns due to the limited rotation of the armature.

From the foregoing description of the structure of my improved pulser, it is apparent that the armature 13 will be attracted to the core 21 upon the energization of the coil 22 and upon such movement, the circuit energizing the coil 22 will be broken by the separation of the contracts thereby permitting -the armature 13 to return to a rest position spaced from the core, at which time the contacts will re-engage. The controlled oscillatory movement of the armature thus produced will producepulsed power to a load device connected across the terminals of the pulser. Because the internal electrical connections are made through utilization of the electrically conductive characteristics of the various structural and magnetic members forming a part of the pulser, the

possibility for loose connections which often shorten the long life needed for such a pulser or vibrator is virtually eliminated. Additionally, the simplicity of the construction together with the uniqueness of the contact yoke suppressor enables an extremely low cost device having high reliability to be manufactured.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. An electromagnetic vibrator comprising a base having an electromagnet mounted thereon, spaced means secured to said base, an armature having a pivot axis, a torsion spring having its ends secured to said spaced means in alignment with the pivot axis of said armature, said armature secured to said torsion spring for rotary oscillation toward and away from said electromagnet, said torsion spring biasing said armature away from said electromagnet, a pair of contacts, and electric circuit means connecting said electromagnet in series with said contacts whereby energization of said electromagnet moves said armature toward said electromagnet to separate the contacts and de-energize said electromagnet.

2. An electromagnetic vibrator comprising an electromagnet having a core and an armature, said armature having a pivot axis, a torsion spring secured to the pivot axis of said armature for supporting the same for movement toward said core when said electromagnet is energized, said spring forming the sole support for said armature and being arranged to oppose movement of said armature toward said core, a pair of contacts urged into engagement when said armature is spaced from said core, means electrically connecting said electromagnet in series with said contacts, and terminals for connecting said pair of contacts and said electromagnet across a source of electrical energy whereby energization of said electromagnet moves said armature toward said core to separate the contacts and de-energize said electromagnet.

3. An electromagnetic vibrator comprising a base and an electromagnet having a core mounted thereon, an armature having a pivot axis, a U-shaped electrically conductive supporting yoke having the ends of its arms secured to said base, a torsion spring secured to said yoke and to the pivot axis of said armature for supporting said armature for movement toward said core when said electromagnet is energized, said spring being arranged to oppose movement of said armature toward said core, a pair of normally closed contacts which are engaged when the armature is spaced from said core, a pair of contacts urged into engagement when said armature is spaced from said core, means electrically connecting said electromagnet in series with said contacts and said yoke, and terminals for connecting said pair of contacts and said electromagnet across a source of electrical energy whereby energization of said electromagnet moves said armature toward said core to separate the contacts and de-energize said electromagnet.

4. The electromagnetic vibrator as set forth in claim 3 including a unidirectional conducting device mounted on the closed end of said yoke and having one side thereof electrically connected thereto, said unidirectional device being poled to conduct the inductive surge of said electromagnet around said contacts upon separation thereof, a second spring secured to the other side of said unidirectional device, a conductive enclosure for said vibrator secured to the base and compressing said second spring, and clip means engageable with said conductive enclosure to support said vibrator and to establish electrical connection to said unidirectional device.

5. An electromagnetic vibrator comprising an electromagnet having a generally cylindrical core and an armature, a spiral spring supporting said armature for movement toward said core when said electromagnet is energized, said armature having an annular portion formed concentric with its pivot axis, said spring being secured within said annular portion to form a support for said armature and being arranged to bias said armature toward said core, a first contact, a second contact mounted on said armature and biased into engagement with said first contact by said spiral spring when said armature is spaced from said core, means electrically connecting said electromagnet in series with said spring and terminals for connecting said first contact and said electromagnet to a source of electrical energy whereby energization of said electromagnet moves said armature toward said core to separate the first and second contacts and de-energize said electromagnet.

6. An electromagnetic vibrator comprising an insulating base, an electromagnet having a core supported on said base, a U-shaped yoke having its ends secured to said base, a torsion spring having its opposite ends secured to the opposed arms of said yoke, a balanced pivotable armature secured to said spring at its pivot axis for rotational movement toward said core when said electromagnet is energized, said spring forming the sole support for said armature and being arranged to oppose movement of said armature toward said core, a flexible contact arm secured to said base and having a first contact thereon, a second contact mounted on said yoke and engaging said first contact when said armature is spaced from said core, means electrically connecting said electromagnet in series with said contacts, and terminals for connecting said stationary contact and said electromagnet to a source of electrical energy whereby energization of said electromagnet moves said armature toward said core to separate the stationary and movable contacts and de-energize said electromagnet.

7. An electromagnetic vibrator comprising an insulating base, an electromagnet having a core supported on said base, an electrical conductive U-shaped yoke having its ends secured to said base, a spiral spring having its ends secured to the arms of said yoke, a balanced pivotable armature secured to said spring at its pivot axis for rotational movement toward said core when said electromagnet is energized, said spring forming the sole support for said armature and biasing said armature away from said core, a flexible contact arm secured to said base and having a first contact thereon, an electrical conductive member bridging the arms of said yoke and having a second contact thereon for engaging said first contact when the armature is spaced from said core, said flexible contact arm having a projection for engaging said armature as the armature moves toward said core, means electrically connecting said electromagnet in series with said yoke and said contacts, terminals for connecting said flexible contact arm and said electromagnet across a source of electrical energy whereby energization of said electromagnet moves said armature toward said core to separate the contacts and de-energize said electromagnet, and a unidirectional conducting device mounted on said yoke and having one side electrically connected thereto, said unidirectional device being poled to conduct the inductive surge of said electromagnet around said contacts upon the separation thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,490,013 12/ 1949 Bramley 20087 BERNARD A. GILHEANY, Primary Examiner.

ROY N. ENVALL, Assistant Examiner. 

1. AN ELECTROMAGNETIC VIBRATOR COMPRISING A BASE HAVING AN ELECTROMAGNET MOUNTED THEREON, SPACED MEANS SECURED TO SAID BASE, AN ARMATURE HAVING A PIVOT AXIS, A TORSION SPRING HAVING ITS ENDS SECURED TO SAID SPACED MEANS IN ALIGNMENT WITH THE PIVOT AXIS OF SAID ARMATURE, SAID ARMATURE SECURED TO SAID TORSION SPRING FOR ROTARY OSCILLATION TOWARD AND AWAY FROM SAID ELECTROMAGNET, SAID TORSION SPRING BIASING SAID ARMATURE AWAY FROM SAID ELECTROMAGNET, A PAIR OF CONTACTS, AND ELECTRIC CIRCUIT MEANS CONNECTING SAID ELECTROMAGNET IN SERIES WITH SAID CONTACTS WHEREBY ENERGIZATION OF SAID ELECTROMAGNET MOVES SAID ARMATURE TOWARD SAID ELECTROMAGNET TO SEPARATE THE CONTACTS AND DE-ENERGIZE SAID ELECTROMAGNET. 